Electrical connectors are used in many electronic systems. Electrical connectors are often used to make connections between printed circuit boards (“PCBs”) that allow separate PCBs to be easily assembled or removed from an electronic system. Assembling an electronic system on several PCBs that are then connected to one another by electrical connectors is generally easier and more cost effective than manufacturing the entire system on a single PCB.
Electronic systems have generally become smaller, faster and functionally more complex. These changes mean that the number of circuits in a given area of an electronic system, along with the frequencies at which those circuits operate, have increased significantly in recent years. Current systems pass more data between PCBs than systems of even a few years ago, requiring electrical connectors that are more dense and operate at higher frequencies.
As connectors become more dense and signal frequencies increase, there is a greater possibility of electrical noise being generated in the connector as a result of reflections caused by impedance mismatch or cross-talk between signal conductors. Therefore, electrical connectors are designed to control cross-talk between different signal paths and to control the impedance of each signal path. Shield members, which are typically metal strips or a metal plate connected to ground, can influence both crosstalk and impedance when placed adjacent the signal conductors. Shield members with an appropriate design can significantly improve the performance of a connector.
High frequency performance is sometimes improved through the use of differential signals. Differential signals are signals represented by a pair of conducting paths, called a “differential pair.” The voltage difference between the conductive paths represents the signal. In general, the two conducing paths of a differential pair are arranged to run near each other. In differential connectors, it is also known to position a pair of signal conductors that carry a differential signal closer together than either of the signal conductors in the pair is to other signal conductors.
Despite recent improvements in high frequency performance of electrical connectors provided by shielding, it would be desirable to have an interconnection system with even further improved performance.